1. Field of the Invention
The present invention relates generally to vehicle-mounted display signs and, more particularly, to vehicle-mounted display signs that are visible from behind the rear window of a front vehicle to warn a following vehicle against following too closely.
2. Description of the Prior Art
The problem of one vehicle following another vehicle too closely ("tailgating") is well known. Throughout the years, a number of innovations have been developed relating to warning drivers of following vehicles that they are following a vehicle in front of them too closely. In this respect, the following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 3,026,498, 4,449,167, and 5,838,228. More specifically, U.S. Pat. No. 3,026,498 employs an apparatus in a front vehicle that has an illuminated sign that warns a following vehicle to keep its distance based upon a light sensor in the front vehicle that detects the headlights of a following vehicle. Such a device is not useful when the following vehicle is not using headlights, such as during the daytime. In this respect, it would be desirable if an illuminated message sign were provided in a front vehicle to warn a following vehicle about following too closely that does not depend upon sensing light from headlights in the following vehicle.
U.S. Pat. No. 4,449,167 discloses an illuminated, rear-facing message sign for a vehicle that depends upon pressing a brake pedal for its illumination. There are times when the driver of a front car wishes to warn the driver of a following car about following too closely, but the driver of the front car wishes to maintain speed, and does not want to put pressure upon the brake pedal. In this respect, it would be desirable if a rear-facing illuminated sign provides warning to a driver in a following car from following too closely without depending upon a brake pedal sensor for activating the illuminated sign.
U.S. Pat. No. 5,838,228 discloses a system for preventing rear end collisions which depends upon electronically sensing a distance between a front vehicle and a following vehicle and calculating a safe following distance factoring in the speed of the vehicles. For purposes of simplicity and direct control by a driver of a front vehicle, it would be desirable if the driver of a front vehicle had manual control over the illumination of a rear-facing message sign for warning a driver in a following vehicle that the vehicle is following too closely.
As a matter of interest, U.S. Pat. No. 4,470,214 discloses a display sign for the rear window of a vehicle. The illumination of the sign is controlled by a driver selectively placing a power plug in a cigarette lighter. The sign itself is illuminated by a light shining on it from the rear-facing side of the sign. Rather than occupy a cigarette lighter, it would be desirable if a manually operated switch were provided for an illuminated sign that is independent of the cigarette lighter. In addition, to provide greater visual contrast between the message of a sign and its background, it would be desirable if the message of the sign were back-lighted.
Also, as a matter of interest, U.S. Pat. No. 5,099,594 discloses a vehicle-mounted message display that uses suction cups for mounting the message display on the inside surface of a rear window of a vehicle. Rather than mounting a message sign on a glass window, to avoid the stresses to the glass that such a mounting entails, it would be desirable if a message display for a rear window sign were mounted on the horizontal surface located between the back of the rear seat and the rear window.
Still other features would be desirable in a vehicle-mounted, rear-directed message display apparatus. For example, when a driver in a front vehicle looks in one's rear view mirror to see if a rear-facing message sign is operating properly, it is difficult to ascertain proper operation. In this respect, it would be desirable if a rear-facing sign had a forward-facing aperture that emitted light when the rear-facing sign is illuminated. In this way, a driver looking in the rear view mirror can see a forward shining light as evidence that the rear-facing sign is working properly.
Different drivers may have different preferences for specific wordings in rear-facing signs. In this respect, it would be desirable if a rear-facing sign had a variety of interchangeable messages that would appeal to a variety of drivers.
Thus, while the foregoing body of prior art indicates it to be well known to use rear-facing message signs in vehicles, the prior art described above does not teach or suggest a vehicle-mounted, rear-directed message display apparatus which has the following combination of desirable features: (1) provides an illuminated message sign in a front vehicle to warn a following vehicle about following too closely that does not depend upon sensing light from headlights in the following vehicle; (2) provides a rear-facing illuminated sign to warn a driver in a following car from following too closely without depending upon a brake pedal sensor for activating the illuminated sign; (3) enables the driver of a front vehicle to have manual control over the illumination of a rear-facing message sign for warning a driver in a following vehicle that the vehicle is following too closely; (4) provides a manually operated switch for an illuminated sign that is independent of the cigarette lighter of the vehicle; (5) provides back-lighting for the message of the sign; (6) provides a rear window sign that is mounted on the horizontal surface located between the back of the rear seat and the rear window of a vehicle; (7) provides a rear-facing sign has with a forward-facing aperture that emits light when the rear-facing sign is illuminated; and (8) provides a rear-facing sign has a variety of interchangeable messages that would appeal to a variety of drivers. The foregoing desired characteristics are provided by the unique vehicle-mounted, rear-directed message display apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.